$green = #02a774
$yellow = #F5A100
$bc = #e4e4e4
// 一像素下边框
bottom-border-1px($color)
    position relative
    &::before
        content ''
        position absolute
        z-index 200
        left 0
        bottom 0
        width 100%
        height 1px
        background-color $color
        transform scaleY(0.5)
// 一像素上边框
top-border-1px($color)
    position relative
    &::before
        content ''
        position absolute
        z-index 200
        left 0
        top 0
        width 100%
        height 1px
        background-color $color
// 根据像素比缩放1px像素边框
@media only screen and (-webkit-device-pixel-ratio 2)
    .border-1px
        &::before
            transform scaleY(0.5)
@media only screen and (-webkit-device-pixel-ratio 3)
    .border-1px
        &::before
            transform scaleY(0.333333)
// 根据像素比来使用 2x图 3x图
bg-image($url)
    background-image url($url + '@2x.png')
    @media (-webkit-min-device-pixel-ratio 3), (min-device-pixel-ratio 3)
        background-image url($url + '@3x.png')
// 清除浮动
clearFix()
    *zoom 1
    &::after
        content ''
        display block
        clear both
